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* Document instance vars better 

* Fuse two parallel loops
* Use a more specific type for AllocaLookup

llvm-svn: 8859
This commit is contained in:
Chris Lattner 2003-10-05 03:16:07 +00:00
parent c360f135be
commit 417bc173ee
1 changed files with 26 additions and 20 deletions
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46
llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
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@ -51,14 +51,20 @@ bool isAllocaPromotable(const AllocaInst *AI, const TargetData &TD) {
namespace {
struct PromoteMem2Reg {
const std::vector<AllocaInst*> &Allocas; // the alloca instructions..
std::vector<unsigned> VersionNumbers; // Current version counters
// Allocas - The alloca instructions being promoted
const std::vector<AllocaInst*> &Allocas;
DominanceFrontier &DF;
const TargetData &TD;
std::map<Instruction*, unsigned> AllocaLookup; // reverse mapping of above
// AllocaLookup - Reverse mapping of Allocas
std::map<AllocaInst*, unsigned> AllocaLookup;
// VersionNumbers - Current version counters for each alloca
std::vector<unsigned> VersionNumbers;
std::vector<std::vector<BasicBlock*> > PhiNodes;// Idx corresponds 2 Allocas
// PhiNodes - Each alloca contains a list of basic blocks which contain PHI
// nodes for the alloca.
std::vector<std::vector<BasicBlock*> > PhiNodes;
// NewPhiNodes - The PhiNodes we're adding.
std::map<BasicBlock*, std::vector<PHINode*> > NewPhiNodes;
@ -84,26 +90,25 @@ void PromoteMem2Reg::run() {
Function &F = *DF.getRoot()->getParent();
VersionNumbers.resize(Allocas.size());
PhiNodes.resize(Allocas.size());
for (unsigned i = 0, e = Allocas.size(); i != e; ++i) {
assert(isAllocaPromotable(Allocas[i], TD) &&
for (unsigned i = 0; i != Allocas.size(); ++i) {
AllocaInst *AI = Allocas[i];
assert(isAllocaPromotable(AI, TD) &&
"Cannot promote non-promotable alloca!");
assert(Allocas[i]->getParent()->getParent() == &F &&
"All allocas should be in the same function, which is same as DF!");
AllocaLookup[Allocas[i]] = i;
}
PhiNodes.resize(Allocas.size());
for (unsigned i = 0; i != Allocas.size(); ++i) {
AllocaInst *AI = Allocas[i];
// Calculate the set of write-locations for each alloca. This is analogous
// to counting the number of 'redefinitions' of each variable.
std::vector<BasicBlock*> WriteSets;
for (Value::use_iterator U =AI->use_begin(), E = AI->use_end(); U != E; ++U)
if (StoreInst *SI = dyn_cast<StoreInst>(*U))
if (StoreInst *SI = dyn_cast<StoreInst>(cast<Instruction>(*U)))
// jot down the basic-block it came from
WriteSets.push_back(SI->getParent());
AllocaLookup[Allocas[i]] = i;
// Compute the locations where PhiNodes need to be inserted. Look at the
// dominance frontier of EACH basic-block we have a write in.
@ -120,12 +125,13 @@ void PromoteMem2Reg::run() {
}
// Perform iterative step
for (unsigned k = 0; k != PhiNodes[i].size(); k++) {
DominanceFrontier::const_iterator it = DF.find(PhiNodes[i][k]);
std::vector<BasicBlock*> &AllocaPhiNodes = PhiNodes[i];
for (unsigned k = 0; k != AllocaPhiNodes.size(); k++) {
DominanceFrontier::const_iterator it = DF.find(AllocaPhiNodes[k]);
if (it != DF.end()) {
const DominanceFrontier::DomSetType &S = it->second;
for (DominanceFrontier::DomSetType::iterator P = S.begin(),PE = S.end();
P != PE; ++P)
const DominanceFrontier::DomSetType &S = it->second;
for (DominanceFrontier::DomSetType::iterator
P = S.begin(), PE = S.end(); P != PE; ++P)
QueuePhiNode(*P, i);
}
}
@ -231,7 +237,7 @@ void PromoteMem2Reg::RenamePass(BasicBlock *BB, BasicBlock *Pred,
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
if (AllocaInst *Src = dyn_cast<AllocaInst>(LI->getPointerOperand())) {
std::map<Instruction*, unsigned>::iterator AI = AllocaLookup.find(Src);
std::map<AllocaInst*, unsigned>::iterator AI = AllocaLookup.find(Src);
if (AI != AllocaLookup.end()) {
Value *V = IncomingVals[AI->second];
@ -244,7 +250,7 @@ void PromoteMem2Reg::RenamePass(BasicBlock *BB, BasicBlock *Pred,
// Delete this instruction and mark the name as the current holder of the
// value
if (AllocaInst *Dest = dyn_cast<AllocaInst>(SI->getPointerOperand())) {
std::map<Instruction *, unsigned>::iterator ai =AllocaLookup.find(Dest);
std::map<AllocaInst *, unsigned>::iterator ai = AllocaLookup.find(Dest);
if (ai != AllocaLookup.end()) {
// what value were we writing?
IncomingVals[ai->second] = SI->getOperand(0);